"Bubba" joins the stable; sorting out EFI issues

[70SWT]

Originally Posted by spuggy

You're welcome; bit of a learning cliff at first eh?

I'm tempted to say it's not too bad so far...but I fear I might create a "hold my beer and watch this" situation if I do...me and Murphy are great buddies...

Seriously, it seems very approachable with the great support in this community.

[70SWT]

Update: I found time to try to make some progress last night.



Since the IAC wiring harness had multiple splices from the PO's trial and error, I removed the connector entirely in order to test it and solder fresh connections with colored heat shrink markers on the connector end:




I got the IAC reinstalled and hooked up as the FAST wiring diagram + the pinout scheme Jamie provided altogether suggested. Here are some shots of the AFR as it warms up:




I don't feel like the AFR changed much over time, other than transiently increasing when I revved the engine. I just need to get it tuned. I still need to figure out the temperature sensor situation.

[BoxsterGT]

I know you are heavily involved in setting this EFI system up to run well, but before you get much further down the road, may I suggest you do something about the hose clamps used with your fuel lines....



I make E-85 Rated "Factory Level" Fuel Hoses for most Porsche models including 911SCs with EFI conversions....



...or at least bring along a fire extinguisher.

I am happy to help with this. Please email me.

Len.Cummings at verizon.net

[70SWT]

Originally Posted by BoxsterGT

I know you are heavily involved in setting this EFI system up to run well, but before you get much further down the road, may I suggest ...

Thanks, will keep that in mind. A variety of upgrades will be to come.

[jpnovak]

The IAC will only function to bleed extra air for warmup rpm when cold. It will not regulate mixture. Did you calibrate the IAC in the panel? There are settings for target rpm as well as correction by the IAC.

You need to look for a cold (warmup) enrichment factor and turn it down. The car is way too rich when cold.



This should be under the "enrichment fuel" tab in the advanced section.

I assume you have a manual. If not, here is a ilnk.
https://static.summitracing.com/global/images/instructions/fst-30400-kit.pdf

Does the AFR change once the car is warm?

[spuggy]

If you're showing 84 mumbles 1 minute after starting and 106 a minute after that, I'm going to go out on a limb and say temp sensing isn't your problem.

if your warmup comps are too rich, simply adding air (via the ICV) will just result in a faster idle - exactly the same as if you opened the throttle - and the same overrich fuel delivery

As for the fuel lines, I'd personally probably reach out to Len.

Otherwise, $50 could improve that for the time being:

https://www.amazon.com/Oetiker-2000-Compound-Action-Pincer/dp/B01IBA4SS0/ref=sr_1_3?crid=2IYU60IRN3OFO&keywords=oetiker+clamps&qid=1572210521&sprefix=oet%2Caps%2C257&sr=8-3
https://www.amazon.com/LOKMAN-Stainless-6-23-6mm-Assortment-Stepless/dp/B07H3Q76QD/ref=sr_1_2?crid=2IYU60IRN3OFO&keywords=oetiker+clamps&qid=1572210521&sprefix=oet%2Caps%2C257&sr=8-2

[70SWT]

I'm getting ready to take another turn at it in the garage in a moment - responses:

Originally Posted by jpnovak

Did you calibrate the IAC in the panel? There are settings for target rpm as well as correction by the IAC.

I didn't do anything further last night than that listed above, just to see how things did with the IAC circuit re-engaged. I see the IAC calibration option on page 46 of the FAST manual, and will try that out.

Originally Posted by jpnovak

You need to look for a cold (warmup) enrichment factor and turn it down. The car is way too rich when cold. This should be under the "enrichment fuel" tab in the advanced section.

And when warm, too, I think...I'm continuing to read through the manual on these adjustments, and will try those items starting on page 50 of the manual.

Originally Posted by jpnovak

I assume you have a manual. If not, here is a ilnk.
https://static.summitracing.com/global/images/instructions/fst-30400-kit.pdf

Yes, that is what I have been working off of.

Originally Posted by jpnovak

Does the AFR change once the car is warm?

No, that's what I was getting at in the last post with the mention on the AFR not changing much with time. It seems that the AFR is just set way too rich overall, if I read things right so far (although the target AFR is much higher than it ever reaches, other than when I rev the engine - I need to read more to see how the target is set).

[70SWT]

Originally Posted by spuggy

If you're showing 84 mumbles 1 minute after starting and 106 a minute after that, I'm going to go out on a limb and say temp sensing isn't your problem.

If I recall correctly, the PO had tried some different approaches to temp sensing to reach the final version, so perhaps it is adequate. Will see what that is, but as you say, it seemed to progressively sense increasing temp over the roughly ten minutes I let it run last night. Will observe that again today to see how it goes vs. the dash gauge.

[70SWT]

The wife cut my fun short with a surprise "honey-do" item, but I was able to determine a couple of things:

1) Since the TB on this car is not from FAST, but has an idle screw, the IAC calibration process should work.

interesting, the FAST EZ EFI 2.0 systems I see online appear to mainly feature the following setup with an integral IAC, for installing EFI on previously carbureted cars:



The manual says to adjust the idle screw to get the box on the monitor into the indicated range - here is what it looks like with the engine cold and off:



My TB looks like this; looks like stock Porsche perhaps other than the TPS:





I ran out of time to explore more...

2) Here is the engine temperature sensor position, which the FAST system sees as a coolant sensor (and which may or may not be a limiting factor as we discussed above): it is located on the driver's side rear of the engine as pictured below:

[70SWT]

I was able to talk to the PO further, and have confirmed that the TB is the original one from the car's CIS system. He says he adapted it to this custom setup only by installing the GM-type TPS, which had to be wired backward to match the plate opening direction, otherwise the TB should be as stock.

[70SWT]

Per this thread here on Pelican...

2.7 CIS WUR and Dizzy vacuum lines routing.

...it looks like the factory idle adjustment screw controls a port in the upper barrel of the TB, above the pivoting throttle plate. Here is a snip from that thread:



The IAC the PO installed is located down on the main body of the intake manifold, as seen here (black upright component with the mini air filter in the lower right foreground):



Unfortunately, I had to work late tonight, so no garage time. Will have time tomorrow to play with this more directly. Hard to find time for projects lately!

[jpnovak]

Time to backup a few steps...

yes, the IAC will run a separate air path compared to the throttle valve. There are 3 main paths controlling the airflow.
1) The throttle plate: It opens when you move the gas pedal. It has the most effect on airflow.
2) the idle bypass screw. This is the large screw behind the throttle body that is accessed from the DS of the engine bay. It controls the amount of air for idle when the throttle is closed. and
3) the IAC. The IAC allows air to pass the throttle plate and idle bypass screw and is also an electronically actuated valve. It should be somewhat open when cold and typically closed when warm.

IMO you don't need to make any changes to the mechanical setup. It is the correct valve for your EFI system and can be properly driven using the 4 wire setup.

Now EFI systems are adjustable but you have to follow a methodical process to get them to work right. Your setup is mechanically different than the manual but you have all the parts. The small idle bypass screw in the bottom of the 4 barrel injection system is the same as the idle bypass screw on the back of the throttle body.

The plunger type GM IAC has a moveable plunger with a nub in the middle. This plunger moves up and down while the nub seats on an opening and acts as a valve. When retracted (cold) the nub opens the valve and allows air to pass through. When extended (hot) the nub closes the valve and prevents air from going through. When in between (warm) the valve moves back and forth to maintain a target idle rpm.

The next step is to determine if the valve actually moves. power on the ECU with the IAC removed from its housing. What does the plunger do? When cold It should retract to allow additional air through. Measure the length of the plunger. Now warm up the car until it runs correctly. Pull out the IAC and see if it is fully extended. The length should change. Now you have confirmed that the IAC is working or not. If not, replace or fix it. Don't move forward until you have successfully passes this test.

Now, Once you pass, you need to see if it affects idle speed properly. In the software configuration you should change your target idle speed. Does the engine speed change. It doesn't have to be perfect yet because you have not calibrated it. If your idle speed changes in the appropriate way (higher when target idle speed is increased and vice versa) then you can calibrate.

Set the desired idle speed in the software panel. Then use the idle adjustment screw behind the throttle body and the moving box dialog panel to make them match. It is very possible that you are allowing too much/little air through the throttle and the IAC can not control the speed. Once you bring it into range you can go do the next step.

Now you have to tune the mixture. First you have to make sure your WBO2 sensor is working properly. Now, warm up the car until it is running properly. You said that it runs and idles well when warm. This is your baseline condition. you should be able to lean the fuel trim and watch the AFR increase. I would expect that as you lean it out you will see the idle speed increase. Once you verify the mixture can be adjusted you are done for the moment.

Next morning or when the engine is cold start the car. YOu have to TUNE the cold start. The idle speed for cold idle can now be adjusted in the FW. Don't touch the idle bypass screw. Let the IAC do the work. Once idle speed is set then move ahead to the cold mixture enrichment. Use the "+/-" adder in cold enrichment to bring the AFR in the 13.1 - 13.5 range.

Best of luck fixing the setup.

[70SWT]

Originally Posted by jpnovak

Best of luck fixing the setup.

Thanks much - I will test the IAC further this evening.

[eastbay]

Did you check out the rest of the weird looking IAC fitting? Does it bottom or seat (shut off) on the the other fitting going into the manifold?

You have the original CIS idle air bypass completely seated? (shut off)

[70SWT]

After tinkering with things for a while, I think I am going to go in a different direction. I have the AFR improved and this system will likely work with a bit more tuning. However, dyne shop time is expensive, and I would like to start fresh with a cleaner appearance and a simpler setup overall, using a system that is specifically set up for 911s. I'd like to go with ITBs but can't justify the cost.

So, I am planning to remove the FAST EFI components and try using the tbitz MS system, while closing up some of the ports on the aluminum airbox that won't be needed for MS, giving a cleaner look. Will likely have it powder coated, fix the sketchy fuel lines, and do about 1000 other things this project needs.

I'm talking to Tony to see how I can move to MS in a cost-effective manner. Stay tuned - no pun intended...

[Flojo]

Originally Posted by 70SWT

rare calipers

[70SWT]

Originally Posted by Flojo

what are these calipers?
wonder what's on the front?

Same type on front. These were popular in years past. They were apparently based on Wilwoods. Lots of threads here and elsewhere on them, e.g.:

Bremtek Racing Calipers

[70SWT]

[Flojo]

Was too quick; found it. thanks

[70SWT]

For anyone who might be interested in fabbing up an intake manifold junction box for the runners when going EFI on a CIS car (instead of cutting down or using the stock airbox), here is what the box looks like as created by the PO. It's a pretty cool piece, actually; looks similar to a couple of others I have seen in my online research on this.

There were a lot of ports tapped into the piece by the PO due to various connections for the FAST setup that I am removing. Once I figure out the minimum number of ports needed to run the Bitz Racing Megasquirt setup (in a conversation with Tony at present), and have the rest of the holes welded up, my plan is to have the box powdercoated before reinstalling.

If you want to see more pics/info, let me know and I will post. For example, in the mountain of records on the car, I recall seeing the templates the PO drew up before cutting and welding the box together.